Help Quiet Awful Intake (?) FM2 Sound
 

Hey...

I am really liking the power of the turbo, but absolutely despising the sound under the right side of the hood under acceleration. Not 100% sure what it is. I love the whoosh sound of the blow off valve, that's not the problem. The problem is that under just about any acceleration, the sound coming from the engine (air filter?) sounds like metal shreds bouncing around (very hard to describe sound and i have never heard this sound on my NA miata or on a Superchargered miata that i remember, but sure hear it on the turbo!

I actually took the custom 3 inch exhaust that had no cat (didnt have to do smog test in Oklahoma) and i took OFF the muffler, and it was loud but i liked it since it mostly drowned out the awful sound from under the hood...now, in Texas and have to add a cat and at least a resonator/muffler, so now the exhaust will be much quieter and i will hear that grating sound upon acceleration all the time. What can i do about this? Is it the K/N air filter making this sound. Is there a way to deaden it?

The car is a 95 so enclosing it in a sound deadened box will not work i dont think since the headlights are right in from of the air filter box and i couldnt run a hose to the front to get air into the filter...

I found this thread about using foam...does that really work? It seems that it would keep air from reaching the air filter at all!

http://forum.miata.net/vb/showthread...r+filter+sound

This sounds petty, but it makes me want to take the turbo off just because of that awful sound...its the only sound i have ever heard from an engine that i hated. I like old sports car loud, but not this weird grating metallic sound...

Thanks!
Randy

It's a 1995 with FMII turbo kit gt2560 by the way...surely there has to be a way to muffle this very hard to explain and loud sound coming from what must be the air filter...again, i love the BOV whoosh sound, hate the continuous sound coming from under the hood upon acceleration...

Randy

the only noise hte turbo should make is a whooshing sound of air being sucked in. anything else is not good...

Metallic rattling.... Does it sound like a bunch of grains of rice being dropped onto a sheet of aluminum foil?

It sounds like you may be experiencing detonation.

is it sad that didn't even cross my mind. marbles in a can?

sounds like detonation. i just recently heard that noise for the first time while trying to road tune my sled. I really dont know how much detonation a car can handle...from what ive read itll blow headgaskets and destroy rod and crank bearings very quickly. really sounded like valve train noise and the funny thing is that the car will still accelerate pretty hard while its happening so its pretty deceptive. when it happened to me i really diddnt know what it was i thought something was rattling around in the trunk cuz i was hauling ass and the car was pulling hard running nice and rich, having never experienced pinging or detonation before i really expected the car to like hesitate or something but nah it still pulls. i thank the car gods that my motor is not knocking but yea man be very careful thats all i can say.

Are you running a Hydra? How much boost are you running? Do you have any logs to upload that are taken during the bad noise?

First of all, its not a new FM2 turbo like a hydra, its the older one...running 9.5 or so lbs of boost...

The sound is during any acceleration and all thru the band at about the same level of sound.

Was thinking on the way to work how to describe the sound...very hard to describe, but maybe imagine air going thru a metal can that has metal pellets in it, and the can spinning upon acceleration, causing the metal pellets to bounce around in the can, along with the loud sound of air going thru the metal can...its very noticeable to me and it really bothers me (only sound that has ever bothered me on a car before!)...again, i was able to deal with it up to now due to having a very loud exhaust mostly drowning it out, but can't do that anymore as Texas law requires a cat and a muffler or resonator...

Hadn't thought about detonation...if it's that, then the car has been doing that for over 5K miles of driving it, wouldn't that have destroyed my engine by now?!

The car is about to be totally retuned by Gary Schuhart of Track Dog Racing in Dallas. He says he can make it run much better, but due to the loudness of the no-muffler exhaust, he didn't really notice the sound i am talking about yet (he will once we put a cat and muffler on it though for sure!). If it IS detonation, then Gary will fix that no doubt...again though, that would have toasted my engine by now, right? So, it has to be something else i would think, and the only thing i can think of is the air filter, and it SOUNDS like the sound is coming from right about there when driving it, but its so hard to tell on sounds where they are actually coming from...

Keith of Flying Miata messaged me and said that you CAN put foam around it (the right kind of foam) and really deaden the sound, and that the intakes on a turbo are much louder than the intakes on a N/A (maybe much loader than on a Sebring Supercharger too, which i had before?), so that is why i am noticing the sound now and didnt on my previous miata, he says.

I need to drive some other people's FM2 turbos and also some K/N filtered NAs and K/N filtered supercharged cars to get a comparison...

Given that the headlights are right in front of the air box, can i build an enclosed box around the air filter and somehow still get air to the filter? Keith of FM also said that FM is working on a enclosed top for the air filter box, but how would air get into the air filter with that?

I know this whole thing sounds petty, but i really hate that sound, and now that my exhaust is going to be not ridiculously loud, i will really hear that sound every time i accelerate, so i have to find a way to get rid of it or it will seriously detract from the enjoyment of driving the car!

Thanks
Randy

Close, read my description below...

What exactly would detonation sound like?

It ALMOST sounds like valves clattering (it has a metallic sound to it on some level, but also an air sound at the same time)...

Again, it is NOT the BOV whoosh sound, that sounds great and is a totally different thing than this constant upon acceleration sound...

Randy
:)

Maybe metal rice being dropped on a sheet of aluminum foil, along with the sound of air in there somehow too...

Randy
:)

That definately sounds like detonation to me. My car does the same rattle sometimes when I hit near 7psi. It's not my tune, it's the fact that my car burns so much oil, and burning oil causes det. It's been like that for a while. If I was running a bigger turbo and more boost, I would've broke something a long time ago. If you're not burning oil, then it has to be in your tune. Are you running a Link?

what you describe sounds exactly like detotation. Is the same noise made when accelerating with little to no boost?

fail thread, lol. I feel for ya man, now get the checkbook out and try again. Where are you in OK?

There is a reason I use electronic det-cans and don't rely on a knock sensor. A lot of "professional tuners" think a knock sensor does the job and that it's archaic technology (the human ear, lol). I've also been running for three years on a "suicide" spark table and tuned 4 track cars that are still running just fine.

I've seen some racecars loud enough that you can't hear detonation in the car on the track, and they run all season, gradually chipping away at pistons and the head.


Wait, is your car that ice-blue color?

Hey Hustler...no, I am back with a good long term job in Dallas (McKinney actually), so Track Dog Racing is close to me (and so are you!)...

Yes, my car is not 'ice-blue' it's powder (think gulf racing or old 60s TR3 blue)...very cool color i think...

Randy
:)

Yes, it makes that sound without boost kicking in i am sure, would have to look at the boost gauge on acceleration again...

This is sounding really bad...leak down and compression test recorded two weak cylinders also, but Gary at Trackdog said that I could go another 2 years or so with living with it burning some extra oil before needing an engine rebuild...

If it is detonation, then can that be fixed with proper tuning, or both proper tuning AND an immediate engine rebuild...engine rebuild is $$$...not good...

Gary has not had a chance yet to play with the car other than a couple of quick spins (with the really loud exhaust, so he claims to not hear the sound i am talking about), so he may quickly figure out its detonation upon starting to retune it...

Randy

By the way, its not one of the new FM2s and i have a megasquirt + LC1

Randy

Trollollollo?

Seriously?

Show us your fuel and spark tables. Is TDR going to use a dyno or drive it up and down the street to tune it?

I am sure he will look at all that when he tunes it (he definitely seems to very capable and honest), i have no idea what they are myself at the moment...not a tuner/gearhead myself...

Randy

Since you have a megasquirt, can you post the tune (MSQ) and some logs?

Not a tuner or a gearhead, but you drive a megasquirted turbo miata? Don't take that as an insult, it's just most people on this site have turbo'd n megasquirted miatas cause they built them.

You don't have to be a gearhead, but at the bare minimum you should know what air fuel ratio your wideband is reading while in and out of boost. You have a gauge, right?

Yeah, please share your wideband readings with us. That's the first place to start.

What's your A/F at idle, cruising, 5 psi and WOT?

Bought the car already built and was running pretty good it seemed to me except for a cold start issue. I didn't have anyone like Gary where i was living before that could help me/teach me...

I don't have the car right now and Gary is going to start really digging into it early next week...we will figure out what is wrong and get the A/F right, etc, plus, with Gary's help, i will learn the basics i need to know about running a car like this. I will never be a gearhead (don't have the time for one thing), but i will learn the basics and get the car right one way or the other...

Thanks for the help everyone...

Remember when you called me and I told you to read on this forum and you told me I had to come over to your house and teach you everything I knew? It takes effort and commitment, zero effort and refusing to read will get you nowhere. This forum will teach you everything you want to know but you need the initiative to do it yourself.

Well, not being defensive, just stating the situation:

1) I am a PCB designer by trade, certainly not harder than setting up a FM2 turbo with MS or rebuilding an engine, but i learn best (i am a bit on the autistic side like my fully autistic daughter) by someone taking me thru what i need to know and me writing down notes, then taking those scribble notes and turning them into various step by step procedures for each thing i have to learn.

Thus, the desire to have someone work directly with me telling me all the basics i need to know...if i was wealthy, i would hire a guru turbo/supercharger guy and literally spend weeks with him learning and writing notes.

Gary has said that he will teach me the very basics on how to properly maintain the car, what to look for, etc.

Until i have that basic knowledge, most of the posts on this particular forum are very confusing for me, and i have spent time reading them and trying to understand them...on miata.net turbo section also...

I have very little time due to driving/working over 60 hours per week, plus being a single dad with two children, one of whom is autistic, so most of my spare learning time at home goes to learning how to heal my daughter...

I have thought of selling the turbo and going NA simply due to wanting to be more simple and at my level of understanding when it comes to cars, plus to save some $$$ to help pay for autism therapies. If i am to keep the turbo, i need to somehow learn the basics i need to know to run a car this intense. Again, the car came already built.

I need a mentor/helper locally more than anything...i could read this forum constantly and still not have a clue about most of what is posted...its not the way i learn for one thing (as i said, i learn by having someone tell me 'You need to know how to do X or Y, you need to check X or Y every week, and here are the steps to do that', then i write notes and now know how to do that and that i NEED to do that)...

That doesn't mean i can't learn anything from just reading this forum, i can, but a lot of it is over my current level of understanding...

I want my miata to be in top notch condition, and would love to have a turbo or supercharger on it, but without someone willing to work with me in the manner i describe (hopefully Gary will fill that role, however at a cost and not as fully as a local friend would), i am not sure i shouldn't part out the turbo and go more basic with a 130whp type NA setup...

Anyway, that's why i wanted to work directly with you Hustler in person, rather than just reading forum posts...

Sorry for the long answer!

Is there anyone in the Dallas area that would work with me in person to get me understanding all the basics about running an FM2 turbo, what to look for, how to datalog, how to fix various things, etc...that would really help me if i decide to keep the turbo...

Randy
:)

Gary has the car right now, will have to post those readings once he gets them...

Randy

How is it possible that a virgin like yourself has children? I assume you adopted.

:giggle:

I remember the injectors being very loud compared to the stock ones... Other than that, maybe post a vid? Did you have someone help you re-tune/datalog the car in OK when you cut up the exhaust?

msq.
 

I think this was the tune that was loaded when you picked up the car. I can't remember... It wasn't polished, needed some tweeking for sure.